Study on Vertical Piles Batter Piles and Pile Groups Under Uplift Load Conditions in Non-Cohesive Sub-soil

Abstract

Model study was carried out in the laboratory to know the effect of uplift loads on vertical piles, batter piles and pile groups. Mild steel piles having 22 mm outer diameter and 1 mm thickness were considered for the study. Different slenderness ratios of 18, 28, and 38 and various angles such as 0°, 15°, 25°, 35°, and 45° were considered for the study. Sand was poured at a fixed relative density in the mild steel tank. The experimental study shows that the pile and pile group attain a maximum value of uplift load capacity when the batter angle reaches to 35°. Further, increase in batter angle causes a reduction in the uplift capacity of the pile. It is also noticed from the experiment that the uplift capacity increases with the slenderness ratio of the pile but its variation is not linear. Pile group of four piles with two vertical piles having L/D ratio 38 and two batter piles of L/D ratio 28 offers same resistance as of the same pile group with all the piles having L/D ratio 38. Numerical modeling was performed using Plaxis-3D to analyse the behavior of vertical piles, batter piles and pile groups under uplift loads. A good correlation between Plaxis-3D results and experimental results was observed.